Verse 9 called the baptism of little children a “solemn mockery,” so Mormon is intentionally repeating the term but here adding the phrase: “putting trust in dead works.” The “dead works” must refer to the baptism of little children. That is the only work in question here and it must contrast with voluntary baptism, an ordinance that requires understanding of the “mercies of Christ.” Why is it a “dead” work? Because it cannot lead to eternal life. It is a work, but nothing in it does what baptism is supposed to do. Therefore, it is a dead work.